The busiest time for air travel in the United States is nearly here.

According to Mike England, a spokesman for the Transportation Security Administration, airports around the country have the most number of fliers in the period from the few days before Thanksgiving through the New Year, compared with any other time of the year. T.S.A. expects to screen an average of 2.4 million fliers a day this year during this period; the average at other times of the year is two million fliers.

Also this year, Airlines for America, a trade association that represents the largest airlines in the United States, projects that 28.5 million passengers will fly on domestic airlines in the 12-day Thanksgiving air travel period, from Friday, Nov. 17 through Tuesday, Nov. 28, a 3 percent increase from 2016.

More fliers undoubtedly mean longer security lines. Enrolling in T.S.A’s PreCheck is one way to get through security faster, but Clear, a biometric screening program offered at 24 airports around the country, may speed up the process even more.

What exactly is Clear, and how is it different from T.S.A. PreCheck?

Here, answers to questions about the program.

What is Clear?

Caryn Seidman Becker, the company’s chief executive, said that Clear uses biometric technology — in this case, either a scan of your fingerprints or an iris scan of your eye — to identify who you are and help you get through airport security quickly.

Biometrics is a technology that verifies a person’s identity through their fingerprints, facial features or other physical characteristics, according Larry Studdiford, a security consultant for airports and the founder of Studdiford Technical Solutions, a security firm in Alexandria, Va. “Biometrics is a virtually foolproof way to determine someone’s identity,” he said. “When it comes to flying, the hope is that biometrics will eventually replace the need for a boarding pass or a passport.”

How does it work?

Once Clear members arrive at the airport, they go through a dedicated Clear lane to a pod where they either scan their fingerprints on a fingerprint reader or look at a camera that can read iris images.

Where is it offered?

Clear is available at 24 domestic airports including John F. Kennedy International Airport and La Guardia Airport, in New York City; Miami International Airport; Los Angeles International Airport; and Hartsfield-Jackson Atlanta International Airport. Clear also operates in seven stadiums including Yankee Stadium and Citi Field, in New York City, and Coors Field, in Denver.

Where can I enroll?

Enrollment can be started online at clearme.com and then completed in person at the airport or at a stadium where Clear is offered so that a company employee can confirm you are who you say you are and link your biometrics with your account.

Does using Clear allow me to bypass T.S.A. screening?

No, said Mr. England of the T.S.A. After passing through a Clear kiosk, members must still go through T.S.A. screening. However, instead of heading to the end of the security line, members go directly to the T.S.A. employee who checks their identification. “Clear gives you ahead-of-line privileges,” Mr. England said.

Are Clear and the T.S.A. connected in any way?

Mr. England said that Clear is not affiliated at all with the T.S.A. Ms. Seidman Becker said Clear is an arrangement between the company and the airport.

How many people are enrolled in Clear, and how does that number compare with T.S.A. PreCheck?

More than 1.5 million people are currently enrolled in Clear, compared with the 15 million or so who are currently enrolled in T.S.A. PreCheck — this latter number includes the more than 5 million travelers who are enrolled directly in T.S.A. PreCheck and the roughly 10 million who are trusted travelers, meaning they have Global Entry, NEXUS or Sentri — programs offered by U.S. Customs and Border protection; travelers who sign up for these programs are automatically enrolled in T.S.A. PreCheck.

How much does it cost to sign-up for Clear?

Anyone can try the program free for a month. Annual membership is $179. Each additional family member who is 18 or older can enroll for $50 while children under 18 can use Clear for free when accompanied by a parent who is a Clear member.

A stadium-only membership is free.

Can I use Clear for both domestic and international travel?

Yes, Clear can be used for both domestic and international departures.

I heard that Delta Air Lines has a partnership with Clear. What does this partnership mean?

Delta SkyMiles members get a discount to use Clear: general SkyMiles members can enroll for $99 while Platinum, Gold and Silver Medallion members can enroll for $79. Diamond Medallion members receive free access to the program.

“Clear is an innovative way for us to streamline the security lines at airports for our customers,” said Kate Modolo, a spokeswoman for the airline.

In addition, Delta is partnering with Clear at Reagan Washington National Airport: Delta SkyMiles members who are enrolled in Clear have the option to use their fingerprints instead of their boarding pass to board any Delta aircraft at the airport and to enter the Delta Sky Club lounge.

But if I’m enrolled in Clear, do I still need a boarding pass at Reagan Airport if I’m not flying Delta? Also, do I need a boarding pass at other airports where Clear is available?

As of now, yes, but Ms. Seidman Becker said that Clear members can expect paperless boarding in the near future.

Will Clear really help me get through security faster if I’m already enrolled in T.S.A. PreCheck?

Possibly, but it’s hard to say how much faster. Mr. England said that the average wait time in a security line for T.S.A. PreCheck fliers is five minutes. And 95 percent of fliers who are not enrolled in T.S.A. PreCheck spend 10 minutes or less waiting in security lines. But Mr. Studdiford said that on a particularly busy travel day, Clear could save fliers anywhere between five and 15 minutes of waiting in a security line.

A version of this article appears in print on November 26, 2017, on Page TR2 of the New York edition with the headline: How a Biometric Screening Program at the Airport Works; and the online version appears with the same title here.

About Integrated BiometricsIntegrated Biometrics, LLC designs and manufactures FBI-certified fingerprint sensors for law enforcement, military operations, homeland security, national identity, election validation, social services, and a wide range of commercial applications. The company’s patented light emitting sensor technology enables lightweight scanners that outperform traditional prism-based devices in size, power consumption, portability, and reliability. Identity management solutions providers, government agencies, and corporations around the world rely on Integrated Biometrics’ products to enroll and verify individual identity quickly and accurately, even in remote locations.